[Composition and characteristics of volatile organic chemicals emission from printed circuit board factories]

Volatile organic chemicals (VOCs) emission were sampled and analyzed from three printed circuit board (PCB) factories in an industrial area in Shanghai. VOCs concentrations, compositions and source profiles were investigated. In September and December, the highest concentration of VOCs from manufacturing spaces in factory A, B and H were (2.94/2.01) x 10(-9), (3.18/1.11) x 10(-6), (0.70/0.18) x 10(-9), respectively; while for the VOCs from the vent of waste gases, they were (0.86/0.90) x 10(-9), (31.2/ 12.0) x 10(-6), (1.24/0.30) x 10(-9), respectively. Factory A total of 67 VOCs compounds of seven classes were detected, such as alkanes and its chlorine substitutes, alkene and its chlorine substitutes, benzene and its chlorine substitutes, ketone group, as well as ester. The highest concentrations in workshop/vent in A, B and H factories were 2-butanone 6.73 mg x m(-3)/2-methyl-n-hexane 5.93 mg x m(-3), ethyl acetate 8.90 mg x m(-3)/propane 9.64 mg x m(-3), and propone 2.04 mg x m(-3)/propone 1.69 mg x m(-3), respectively. With 100% detection rate, the highest and average concentrations of benzene, toluene and xylene of all sampling sites were 0.077 mg x m(-3)/ 0.035 mg x m(-3), 0.56 mg x m(-3)/0.31 mg x m(-3), 0.21 mg x m(-3)/0.12 mg x m(-3) (m-xylene + p-xylene) and 0.081 mg x m(-3)/0.050 mg x m(-3) (o-xylene), respectively. According to the results of source profiles and PCA analysis, benzene, toluene, xylene, acetone and 2-butanone could be defined as the molecular markers for A and B factories. For factory H, molecular markers were alkanes chlorine substitutes and alkene chlorine substitutes, as well as benzene and its chlorine substitutes. Non-point source was located in the workshops and the production lines. Point source pollution of VOCs was from the vent of waste gases.